William Evans, the acting Boston police commissioner and a 31-year-veteran of the force, will be named to the permanent post Thursday, Mayor Martin J. Walsh’s office said Tuesday night.

“Commissioner Evans has been an exceptional leader to the Boston Police Department, and public safety is one of my biggest priorities,” Walsh said in a corrected statement early Wednesday. “Commissioner Evans has been an invaluable resource to me during this transition period, and I know that his expertise and governance of the Police Department will be a key component to my Administration.”

An earlier press release contained a Walsh statement that had previously been attributed to former Mayor Thomas M. Menino. Early Wednesday, Walsh’s office sent a new statement attributed to Walsh.

A police spokeswoman said Evans, 55, will not be available for comment on the appointment until a press conference Thursday.

The quiet, unassuming officer, who has been captain of two districts, was one of the first commanders to reach the Boston Marathon scene after two bombs killed three people and injured more than 260 on April 15 of last year.

Evans had just finished running the race and was heading home to change when the bombs went off near the finish line. In the aftermath, Evans calmed officers, department officials have said, counseling them to remember their training and not act rashly as they searched for the suspects.

Evans also received accolades for his handling of the 70-day Occupy Boston encampment that was dismantled by police in a generally peaceful fashion in December 2011. He won over many of the protesters at the time, giving out his cellphone number and eventually getting theirs.

“Our motto is to kill them with kindness,” he said then.

Councilor Matt O’Malley said Tuesday night that Evans is a solid choice for the job.

“I think it’s a very good choice,” said O’Malley, who has served on the council’s Public Safety Committee. “Commissioner Evans has impressed me the last three years that I’ve been on the council working with him. He’s always been accessible. He’s very smart and detail-oriented, and his leadership in the aftermath of the Marathon bombings really impressed me.”

Another councilor, Tito Jackson, also had high praise for Evans.

“I think he has a history of achievement in the Boston Police Department and a track record of community engagement,” Jackson said.

The administration of Evans’s predecessor, Commissioner Edward F. Davis, had clashed in the past year with a prominent minority officers’ advocacy group led by Larry Ellison, a Boston detective.

Among the charges Ellison leveled at Davis was the allegation that he did not do enough to diversify the command staff, a charge that Davis vigorously denied.

Ellison offered his congratulations to Evans Tuesday night in a phone interview.

“I wish him well, and I look forward to working with him,” Ellison said.

Asked if he believed that Evans would be more receptive as commissioner to the concerns of his organization, the Massachusetts Association of Minority Law Enforcement Officers, Ellison sounded an optimistic note.

“In the conversations we’ve had, he already has been,” said Ellison. “The relationship has already been very positive since he’s been the acting commissioner.”

Evans is the brother of Paul Evans, who led the department from 1994 to 2003.

William Evans joined the department as a patrol officer in 1982 and rose through the ranks before becoming captain, first in Brighton and Allston, then in busy District 4, which covers the South End and the Fenway area. He was promoted in 2009 to superintendent in charge of the Bureau of Field Services, a position responsible for overseeing special events and the patrol division.

Rufus Faulk, a program director with the Boston TenPoint Coalition, which works with at-risk youth to stem gang violence, was also high on the pick Tuesday night.

“My first thought is just congratulations to Bill,” Faulk said. “He’s served the city valiantly, and I know he’ll probably do a great job as commissioner.”